Comparing electric fields with gravitational fields
Section: Electric Fields | Syllabus: Cambridge A Level Physics (9702)
Similarities and Differences
Both electric and gravitational fields describe how objects with certain properties (charge or mass) interact across space without contact.
| Feature | Gravitational Fields | Electric Fields |
|---|---|---|
| Source | Mass (m) | Charge (Q) |
| Force Law | Inverse Square (F ∝ 1/r^2) | Inverse Square (F ∝ 1/r^2) |
| Type of Force | Always Attractive | Attractive or Repulsive |
| Field Strength | g = (GM/r^2) (Radial) | E = (Q/4π_0 r^2) (Radial) |
| Potential | Always Negative (V = -(GM/r)) | Positive or Negative (V = (Q/4π_0 r)) |
| Work Done | W = mΔ V | W = qΔ V |
The pattern of field lines for a point mass is identical to that of a point negative charge (both radial and directed inwards).
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